Haworth projection

File:Haworth projection of α-D- and α-L-Glucopyranose.svg

Haworth projection of the structures for α-D-glucopyranose and α-L-glucopyranose.

A Haworth projection is a common way of representing the cyclic structure of monosaccharides with a simple three-dimensional perspective.

The Haworth projection is named after the British chemist Sir Norman Haworth.

A Haworth projection has the following characteristics:

• Carbon is the implicit type of atom. In the example on the right, the atoms numbered from 1 to 6 are all carbon atoms. Carbon 1 is known as the anomeric carbon.
• Hydrogen atoms on carbon are implicit. In the example, atoms 1 to 6 have extra hydrogen atoms not depicted.
• A thicker line indicates atoms that are closer to the observer. In the example on the right, atoms 2 and 3 (and their corresponding OH groups) are the closest to the observer. Atoms 1 and 4 are further from the observer. Atom 5 and the other atoms are the furthest.
• The groups below the plane of the ring in Haworth projections correspond to those on the right-hand side of a Fischer projection. This rule does not apply to the groups on the two ring carbons bonded to the endocyclic oxygen atom (the one that is part of the pentagon-shaped ring).

See also

• Structural formula
• Fischer projection
• Natta projection
• Newman projection
• Monosaccharide